Bowel Obstruction: Symptoms, Types, Causes and Treatment

Bowel obstruction is a common and potentially life-threatening condition where the normal flow of intestinal contents is blocked. Whether caused by a physical barrier or by factors outside the bowel, obstruction can quickly lead to complications if not recognized and treated promptly. In this article, we’ll explore the key symptoms, the different types of bowel obstruction, their causes, and the latest approaches to treatment—helping you understand what to look for and what to expect if you or someone you care for faces this challenge.

Symptoms of Bowel Obstruction

Bowel obstruction often announces itself through a collection of symptoms that can range from mildly uncomfortable to acutely distressing. Recognizing these signs early can make a significant difference in timely diagnosis and management.

Symptom	Description	Frequency/Significance	Source(s)
Pain	Crampy or colicky abdominal pain	Most common, often intermittent	1 2 3 4 13
Nausea/Vomiting	Sensation/act of vomiting due to blockage	Common, may be severe	2 3 4 13
Distension	Swollen, bloated abdomen	Classic finding	1 3 4 13
Constipation	Inability to pass stool and/or flatus	Key sign of complete obstruction	1 2 3 13
Tenderness	Abdominal tenderness to touch	May indicate complication	2 3 13
Dehydration	Signs like dry mucosa, tachycardia	Due to fluid loss	13
Fever	Elevated body temperature	Suggests infection/complication	2 4 13

Table 1: Key Symptoms

Understanding the Symptoms

Most patients with bowel obstruction experience a combination of the symptoms above, but the severity and order can differ depending on the obstruction's location and cause.

Crampy Abdominal Pain

• Nature: Pain is often described as crampy or colicky, coming in waves as the intestine tries to push contents past the blockage.
• Location: The pain may be generalized or localized, depending on the site of the obstruction 1 3 13.

Nausea and Vomiting

• Vomiting is more prominent in small bowel obstruction and may be bilious or feculent if the blockage is lower down 3 4.
• Persistent vomiting can lead to dehydration and electrolyte imbalances.

Abdominal Distension

• The abdomen often appears visibly swollen and may feel tense.
• Distension is more noticeable in obstructions of the lower small bowel or colon 1 3.

Constipation and Obstipation

• Constipation: Initially, patients may find it difficult to pass stool.
• Obstipation: In complete obstruction, there is a total inability to pass stool or even gas (flatus), a hallmark sign 1 2 3.

Additional Signs

• Abdominal tenderness: May suggest underlying inflammation or perforation.
• Dehydration: Dry mouth, low urine output, and rapid heart rate are common due to vomiting and third-spacing of fluids 13.
• Fever and sepsis: High fever or signs of systemic infection indicate complications such as bowel ischemia, necrosis, or perforation 2 4 13.

Types of Bowel Obstruction

Bowel obstruction is not a single entity—it can occur in various forms, each with unique implications for management and prognosis.

Type	Description	Key Features	Source(s)
Mechanical	Physical blockage of the bowel	Adhesions, hernias, tumors	1 2 3 4 13
Functional	Impaired movement without blockage	Ogilvie’s syndrome, paralytic ileus	2 3
Small Bowel	Obstruction in small intestine	More vomiting, rapid onset	1 3 7 8 13
Large Bowel	Obstruction in colon	More distension, less vomiting	1 6 10
Partial	Incomplete blockage	Some passage of gas/stool	2 6
Complete	Total blockage	No passage of gas/stool	2 4 13

Table 2: Types of Bowel Obstruction

Mechanical vs Functional Obstruction

• Mechanical obstruction means there’s a physical barrier preventing movement—like a tumor, hernia, or scar tissue (adhesion) 1 2 3 13.
• Functional obstruction (or pseudo-obstruction) occurs when the bowel stops moving (paralysis), but no physical barrier is present. This can happen after surgery, with certain medications, or in severe illness 2 3.

Small vs Large Bowel Obstruction

• Small bowel obstruction (SBO): More rapid onset, pronounced vomiting, and less distension.
• Large bowel obstruction (LBO): Slower progression, more marked distension, constipation more prominent, vomiting occurs later 1 6 10.

Complete vs Partial Obstruction

• Complete: No passage of stool or gas, high risk of complications.
• Partial: Some material still passes; symptoms may be less severe and can sometimes be managed without surgery 2 6.

Causes of Bowel Obstruction

Understanding the underlying causes of bowel obstruction is key to choosing the right treatment strategy. Causes can vary by age, geography, and previous medical history.

Cause	Brief Description	Prevalence/Notes	Source(s)
Adhesions	Scar tissue from surgery/inflammation	Leading cause in developed world	1 3 7 8 13
Hernias	Bowel trapped in abdominal wall defect	Common, high risk of strangulation	1 7 8 13
Tumors	Cancerous growths in bowel wall	More common in large bowel	1 3 6 8 12
Volvulus	Twisting of bowel loop	Sigmoid, cecal, small bowel	7 9
Intussusception	Bowel telescopes into itself	Common in children, some adults	7 9
Inflammation	Crohn’s, diverticulitis	Causes narrowing/strictures	7 8
Foreign bodies	Bezoar, gallstone, worms	Rare, more in elderly/children	7 13
Radiation	Bowel wall scarring after radiation	Rare, delayed complication	7 8

Table 3: Main Causes of Bowel Obstruction

Adhesions

• Form after abdominal or pelvic surgery; they are strands of scar tissue that can kink or tether the intestines.
• Responsible for up to 65–75% of small bowel obstructions in Western countries 1 7 8 13.
• Adhesions may also form after severe inflammation, such as from appendicitis or pelvic inflammatory disease.

Hernias

• Occur when part of the intestine pushes through a weak spot in the abdominal wall and becomes trapped.
• Most dangerous when “incarcerated” (not reducible), as this can cut off the blood supply, leading to strangulation and tissue death 1 7 13.

Tumors

• Cancerous tumors can grow into the bowel and block the lumen, or compress the bowel from outside.
• In the large bowel, colorectal cancer is a leading cause of obstruction, especially in older adults 1 6 8 12.

Volvulus

• The bowel twists on itself, cutting off its own blood supply.
• Sigmoid volvulus is the most common type in adults, while small bowel volvulus is also seen 7 9.

Intussusception

• Occurs when one section of bowel slides into the next, like a telescope.
• More common in children but does occur in adults, often related to a tumor serving as a “lead point” 7 9.

Inflammatory and Other Causes

• Chronic inflammatory conditions (Crohn’s disease, diverticulitis) can cause scarring and strictures, narrowing the bowel 7 8.
• Rare causes include gallstones, bezoars (masses of swallowed material), worms, or foreign bodies 7 13.
• Previous radiation therapy can cause delayed scarring and narrowing in the bowel 7 8.

Treatment of Bowel Obstruction

Managing bowel obstruction is a balance between conservative/supportive care and timely surgical intervention. The choice depends on the cause, severity, and presence of complications.

Treatment	Description	Indication/Key Points	Source(s)
Supportive	IV fluids, bowel rest, decompression	First-line for stable, uncomplicated cases	3 4 11 13
Surgery	Removal of blockage, resection	Complications or failed conservative care	1 3 4 11 13
Stenting	Placement of metal stent	Malignant/selected obstructions	5 12 15
Medication	Analgesics, antiemetics, antibiotics	Symptom control, infection, palliative care	4 5 15
Palliative	Symptom relief in advanced cancer	Malignant, inoperable cases	5 14 15

Table 4: Main Treatment Strategies

Supportive (Non-Surgical) Management

• IV Fluid Resuscitation: Correct dehydration and electrolyte imbalances caused by vomiting and third-space losses 3 4 13.
• Bowel Rest: Patients are made nil per os (nothing by mouth) to reduce further accumulation of fluid and gas 3 4 11.
• Nasogastric Decompression: A tube is inserted into the stomach to remove fluid and air, relieving distension and vomiting 3 4 13.
• Monitoring: Regular assessment for signs of deterioration (pain, fever, peritonitis) is crucial.

Non-operative management is often successful, especially for adhesive small bowel obstruction without signs of strangulation or perforation 11 13. However, careful selection and monitoring are vital, as delayed intervention in complicated cases increases the risk of death 1 3 4 13.

Surgical Intervention

• Indications: Signs of bowel ischemia, necrosis, perforation, peritonitis, or failure of supportive care within 24–72 hours 1 3 4 11 13.
• Procedures: May include removal of the obstructing lesion, adhesiolysis (cutting adhesions), hernia repair, or bowel resection with or without reanastomosis 9 11.
• Laparoscopic vs Open Surgery: Minimally invasive surgery may be possible in some cases and can reduce the risk of further adhesions 11 13.

Endoscopic and Stenting Approaches

• Self-Expanding Metal Stents: Used in malignant obstruction of the colon or upper GI tract to relieve blockage, either as a bridge to surgery or for palliation 5 12 15.
• Endoscopic Decompression: May be attempted in select cases of sigmoid volvulus or pseudo-obstruction.

Medical and Palliative Approaches

• Analgesics and Antiemetics: Pain and nausea control, particularly important in palliative care 5 15.
• Antibiotics: Used if there is evidence of infection, perforation, or high risk of bacterial translocation 4 13.
• Somatostatin Analogues: Reduce GI secretions and vomiting in malignant or high-level obstruction 15.
• Palliative Care: For malignant bowel obstruction not amenable to surgery, focus shifts to symptom control, communication, and patient comfort 5 14 15.

Individualized Care

• Management decisions should be tailored to the patient’s overall health, cause of obstruction, and goals of care, especially in cases involving malignancy or poor surgical candidates 5 12 14 15.

Conclusion

Bowel obstruction is a complex clinical problem demanding rapid recognition and a tailored approach to management. Here’s a summary of the key points:

• Symptoms: Abdominal pain, distension, vomiting, and constipation are classic; severity and order depend on location and cause.
• Types: Obstructions may be mechanical or functional, affect the small or large bowel, and be partial or complete.
• Causes: Adhesions, hernias, tumors, volvulus, intussusception, and inflammatory diseases are primary culprits, with variations by age and geography.
• Treatment:
  • Supportive care is first-line for uncomplicated cases.
  • Surgery is necessary for complications or failed conservative management.
  • Stents and endoscopic techniques play a role, especially in malignancy.
  • Palliative care and symptom management are central for advanced or inoperable disease.

Early diagnosis and appropriate intervention are critical to improving outcomes and reducing complications in bowel obstruction. If you or someone you know experiences these symptoms, prompt medical attention is vital.